Manufacture of evacuated vessels



Oct. 12 1926. 1,602,634 w. E. ANDERSON MANUFACTURE OF EVACUATED VESSBLS Filed May Z'I, 192g TO VHCUUM PUMP FED/1 Sal/E05 OF OXYGEN INVENTQR WALDEMAR E HNDERS ON BY ATTORNEY Patented ocalz, 1926.

UNITED STATES 1,602,634 PATENT OFFICE.

WALDEm ENOCH ANDERSON, OF GREAT NOTCH, NEW JEREY, ASSIGNOB. T WES'I' INGHOUSE LAMP COMPANY, A COBIORATION OF PENNSYLVANIA.

MANUFACTURE OF EVACUATED VESSELS.

Application filed May 27,

This invention relates to the evacuation of bulbs and other containers and more particularly to the production of proper degrees of vacuum in incandescent lamps.

I An object of my invention is the replacement of the air normally present in a vessel by an entirely chemically active gas so that, when the vessel is evacuated, the residual gas remaining will be adapted to combine readily with a substance used for a final clean- Another object of my invention is the elimination of inert gas from a vessel to an extraordinary fine degree so that, upon the l exhaustion thereof, a .getter may e provided that will combine readily with the residual s to produce a good vacuum.

A furt or object of my invention is the production of the vacuum desired, in the manufacture of incandescent lamps and other evacuated vessels, by flushing the same repeatedly with oxy en or some other active gas, exhausting sue gas and cleaning up the residue thereof by means of phosphorus or some other substance with a strong afiinity for said gas. a

A still further object of my invention is to eliminate the necessity of utilizing the slow-acting vacuum pumps which are ordinarily necessary to produce the desired degree of vacuum in a lamp bulb.

Other objects and advantages will be apparent as the description proceeds.

In exhausting vacuum lamps, it has been customary to reduce the pressure of the air therein to a small amount by means of a vacuum pump and then tip ofi the bulb, which contained a tter adapted to absorb the remainder of t e oxygen in the bulb.

40 By this method, there was always an appreciable amount of nitrogen and other inert gases left in the bulb unless an exceedingly eflective vacuum lpump was employed. This inert residue, alt ough it did not attack the filament was disadvantageous in that it reduced the efficiency of the lamp by causing a loss of heat'by convection through the residual Accor in to my inventiombl replace the e air norma y present in a bul or container with a substantially pure gas, such as oxygen, chlorine or other chemically active The gas is preferably oxygen which i strong chemical properties and a residue thereof is, therefore, readily eliminated by almost an 1922. Serial 110. 564,014.

ordinary getter. Specifically, my metho consists, brlefly, in heating the bulb to expel moisture from the lass, exhausting the bulk of the air therefrom, flushing the bulb with oxygen, exhausting again and repeating the flushing and exhausting preferably two or three times to eliminate the last traces of inert gas. After exhaustin for the last time, the bulb is tlpped 0 the getter in the bulb being adapted to clean up the final traces of oxygen when the lamp is flashed.

In the accompanying drawing which illus trates a preferred embodiment of my invention,

Fig. 1 is an elevational view showing an incandescent lamp bulb and connections thereto for carrying out my method of exhausting the same;

Fig. 2 is an elevational view of a portion of a mount for an incandescent lamp, illus- .trating a form of getter which may bepsed in connection therewith;

Fig. 3 is a similar view illustrating a modification; and,

Fig. 4 is a similar view illustrating a fur- ,ther modification.

A lamp bulb or other vessel 1 (Fig. 1) is provided with a mount 2 in any suitable manner. Applied to the mount 2, before 35 the same is sealed into the bulb 1, is any getter substance adapted to combine actively with oxygen or other active gas which may be used according to my invention. The bulb is preferably heated to from 300 to 400 C. to drive off all moisture therefrom. The same while still hot then may be connected to the exhaust system 3, by means of rubber tubing 4 and contraction tube 5. Connected to the exhaust system 3 is a suitable vacuum gage 6. A source of oxygen (not shown) also may be connected thereto by means of a connection 7 This source may be connected or disconnected from the bulb 1 by suitablemanipulation of the valve or. stop cock 8. Also connected to the exhaust system 3, as bymeans of rubber tub- 12% 9, is a vacuum pum or other means for austion (not shown, 'Anothe r similar valve or stop cook 11 me" serve to connect the vacuum pump to or isconnect it from thebulbl. I

The 0' eration of m invention is as follows. ith'valve 8 c osed, the valve 11 1s turned to allow the bulb to be exhausted by 1 means of a vacuum pump such as is used for a first-stage exhaust for lam bulbs, to a pressure of from to mms. 0 mercury, as indicated on the gauge 6. The pum is then shut off from the bulb by turning t 1e valve 11, and the valve 8 is turned to admit oxygen to the exhausted bulb. These operations are preferably repeated. that is, the air first, then oxygen, is exhausted and the bulb flushed out by fresh oxygen, preferably two or more times before the oxygen is finally exhausted by the vacuum pump and the bulb tipped off. The residual gas remaining in the bulb, after treating according to my method, is practically pure oxygen which is adapted to be substantially completely eliminated by any usual getter.

' Referring now particularly to Fig. 2, l have shown a partial view of a mount for an incandescent lamp with a preferred form of getter applied thereto. The mount 2 may comprise an arbor 12 to which is attached a tube'13, as by means of a glass or metal rod 14 secured to the arbor 12. The tube 13 may be made of glass or other convenient substance. not attacked by the getter and contains preferably a heating coil 15 of relatively low electrical resistance compared tothe lamp filament and of some readily oxidizablemetal, such as aluminum, connected in shunt across the leading-in wires 16 and 17. Packed around the wire 15 may be red phosphorus or other substance adapted to readily combine with the residual gas when heated. Each end of the tube 13 is preferably plugged with some inactive porous substance, such as glass wool,-for the purpose of confining the phosphorus.

,It is readil apparent that, with a etter of the form d escribed, when the lamp 1s energized from a suitable source of electricity,

the phosphorus or other substance is heated by the coil 15 and thereby vaporized when it combines with the residual oxygen, with the production of phosphorus pentoxide and the formation of a good vacuum. The wire coil 15 of aluminum will also assist, by burning out when heated,;in absorbing the last traces of oxygen, if suflicient phos-. phorus is not provided for this urpose.

Another form of getter is illustrated in F1g. 3 which shows a partial mount 2 the leadmg-m wires 16 and 17 of which ave connected thereacross a supplemental or auxiliary getter filament 18 preferably of relatively low electrical resistance compared to the lamp filament and composed of aluminum, magnesium, calcium or other metal having a strong aflinity for the gas residue. This getter may be activated and subsequently burn out when the lam is first energized'or lighted, thus combimng with J the residual oxygen to form solid compounds and resulting in a very ood vacuum. a Fig. 4 showsa furt er modification of my gettering arrangement. The mount 2 is provlded with a tungsten filament 19, formed in the usual manner and to which may be applied agetter formed of finely divided aluminum or other suitable powder, such as red phosphorus mixed with some suitable bindlng' material, such as the cellulose binder now commonly used by lamp manufacturers. As an alternative, the filament 19 may be formed of an inner core of tungsten and an outer coating of aluminum or other suitable metal in a 'manner similar to that in which Dumet wire is formed. The aluminum sheath on the tungsten wire makes it possible to i draw the wire without as much die wear as is usual when pure tungsten wire is drawn.

It will be apparent that my invention provides means for readily producing an evacuated bulb or container in which the residue is oxygen or other chemically active gas. which is adapted to be completely eliminated by the getter instead of, as heretofore, comprising a part of inactive gas, which will remain and be a source of inelliciency even after the getter is activated. It is also apparent that my invention provides means by which the slow-acting vacuum pumps, which are ordinarily necessary to producea suitable vacuum, may be dispensed with, as it is necessary to evacuate the lamps or containers initially only to such a degree as is accomplished by reciprocating pumps, of the type used for first-stage exhaustion in the manufacture of incandescent lamps.

While I have illustrated What I now consider to be a preferred embodiment of my invention, it is to be understood that minor changes may be made thereinand that the same is to be limited only by the scope of the appended claims.

Whatis claimed is:

1. The method of evacuating a container comprising replacing the air therein by a gas which is substantially free from water vapor and chemically active with respect to a given clean-up agent, pumping out said gas and removing the residue by vaporizing said clean-up agent in the container.

2. The me'thodof exhausting a lamp bulb or other container comprising replacin air therein by substantially pure oxygen-an exhausting said oxygen whereby the residue therein is substantially completely-active and cleaning up such residue by a vaporizable getter contained within the bulb.

3. The method of producing a vacuum in a container comprising eliminating air therefrom by anoxygen flush, reducing the pressure of the oxygen therein to asmall amount sealing oil the container and cleaning up the residual oxygen by a suitable substance in the container.

4. The method of reducing a vacuum in a lamp bulb or the lilre comprising flushin the same with oxygen, exhausting sai oxygen to leave only a small pressure therein and cleaning up the oxygen remaining by means of phosphorus getter contained within the bulb. 1 V

5. The method of producing a vacuum in a lamp bulb or the like comprising flushing the same with oxygen, exhausting said oxygen to leave only a small pressure therein and cleaning up the oxygen remaining by means of a substance contained within the bulb which when heated combines actively therewith. i

6, The method of exhausting a gas tight container comprising evacuating the air therefrom, replacing said air by a gas which is substantially free from water vapor and chemically active with regard to a given clean-11p material, evacuating said gas and replacing the same'by a fresh supply thereof, again evacuating the container and absorbing the residue by vaporizing said getter therein to cause the getter to combine with said residue.

7. The method of evacuating a bulb for an incandescent lamp comprising exhausting and refilling the bulb several times in succession with oxygen to thereby eliminate all traces of inert gases, exhausting the oxygen from said bulb and removing the last traces of oxygen therein by means of the phosphorus getter in the bulb.

8. An incandescent lamp comprising an evacuated bulb, a residue therein free from water vapor comprising a completely active gas and a getter adapted to efficiently clean up said residue.

'9. An incandescent lamp comprising an exhausted bulb, a gas residue therein free from water vapor comprising substantially pure oxygen and a phosphorus getter adapted to eliminate efiiciently said residue.

10. An incandescent lamp comprising an exhausted bulb, a substantially pure oxygen residue therein and a getter comprising a substance having a strong affinity for oxygen when heated.

11. An incandescent lamp comprising an evacuated bulb free from moisture and con taining a substantially pure oxygen residue therein at low pressure and red phosphorus adapted to be heated for combining with the oxygen when the lamp is energized.

12. An incandescent lamp comprisingan evacuated bulb, a getter therein comprising red phosphorus packed in a tube and held therein by glass wool, a coil of aluminum wire passing through said phosphorus and inshunt with the leading-in wires, the bulb being free from Water vapor and containing a residue of oxygen at low pressure adapted to be eliminated by said getter.

13. A getter device for an incandescent lamp comprising a tube containing red phosphorus and an aluminum conductor extending through said tube in contact with said phosphorus for the activation thereof.

' 14. A getter for an incandescent lamp comprising a coil of aluminum in contact with red phosphorus which it is adapted to activate. v

In testimony whereof, I have hereunto subscribed my name this 26th day of May 1922.

WALDEMAR ENOGH ANDERSON. 

